A graduate student named Andrew Rushby from the University of East Anglia in Britain recently created two equations able to estimate how long life on Earth can continue to exist. The two equations were designed to estimate the length of time that the Earth is expected to remain within our solar system's habitable zone.
The habitable zone of the solar system is the zone where the planet is neither too close to the sun to prevent liquid water from existing nor too far from the sun to prevent liquid water from being frozen solid. According to the equations, life on Earth has only 1.75 to 3.25 billion years left.
It's definitely a huge range, and it assumes that some other catastrophe doesn't end life on Earth before then. According to the scientists, as our sun ages it will become a larger and brighter star. As it becomes larger and hotter, the Earth will move from being firmly in the habitable zone as it is now to being too hot to support liquid water.
Once the planet moves out of the habitable zone it will be in what astronomers call the hot zone. In the hot zone, liquid water and life as we know it will cease to exist on Earth. It wasn't the intent of these equations to be used simply to predict how long life can continue on Earth.
The scientist created the equations to help astronomers determine whether newly discovered planets out in space are in the habitable zone around their host star and how long they will remain there. Rushby said:
Humans would be in trouble with even a small increase in temperature, and near the end only microbes in niche environments would be able to endure the heat.